Series numeration from Fantastic Fiction.

"After some post-Christmas retail therapy in the Windy City, mystery bookshop owner and historical whodunit novelist Sam Washington is returning home to North Harbor, Michigan, on a chartered bus. With Nana Jo and her gal pals Irma, Dorothy, and Ruby Mae from Shady Acres Retirement Village along for the ride, it's a lively trip. But one passenger is not so lively-a gentleman Irma befriended is found dead in his seat after an unscheduled stop. The ladies immediately shift gears to find out who punched his ticket, while Sam slips into the driver's seat to make sure Nana Jo and her crew steer clear of fatal conclusions . "-- Provided by publisher.